A good Samaritan can save the life of someone in cardiac arrest if a portable defibrillator is nearby. Now, a pilot study suggests a new way to get the devices into bystanders' hands: drones.
The study, done in Sweden, found that drone delivery was a feasible way to get automated external defibrillators, or AEDs, to the scene of a cardiac arrest.
In fact, the drones typically beat ambulances by a couple of minutes.
Since those minutes can mean the difference between life and death, the early findings are encouraging, researchers said.
However, drone-delivered AEDs are far from prime time.
"This points to a non-traditional route for addressing a problem we've had for a long time," said Dr. Jennifer Silva, a member of the American College of Cardiology's Health Care Innovation Council.
"In general, I love the concept of using technological advances to improve the way we practice medicine," said Silva, who was not involved in the study.
In this case, she said, the findings suggest it's possible to deliver AEDs by drone. But the big question, Silva stressed, is whether that can ultimately make a difference in cardiac arrest victims' outcomes.
Cardiac arrest occurs when the heart's normal rhythm stops suddenly, making the muscle incapable of delivering blood and oxygen to the body. It causes unconsciousness within seconds and is fatal within minutes -- unless a bystander performs chest compressions or uses an AED until paramedics arrive.
AEDs are portable versions of the defibrillators doctors use to "shock" the heart back into a normal rhythm. The devices automatically analyze a person's heart rhythm to gauge whether a cardiac arrest is in progress.
"They are incredibly user-friendly," Silva explained. "They literally talk you through the steps, and tell you when a shock should be delivered."
AEDs are often available in public places, she noted, including schools, airports, sports venues, retail stores, and office buildings.
But most cardiac arrests happen at home, where AEDs are rarely available, said Dr. Sofia Schierbeck, of Karolinska University Hospital, in Stockholm, Sweden.
That's a particular dilemma if an ambulance cannot arrive quickly.
So Schierbeck and her colleagues wondered whether drones could step in.
In a pilot study, they had three AED-equipped drones integrated into a regional medical system covering about 80,000 people.
When a suspected cardiac arrest was reported to emergency services, both an ambulance and, if possible, a drone was dispatched.
Over three months, 53 possible cardiac arrests were called in. A drone was dispatched to 12. In the other cases, drones couldn't be sent because of weather or darkness or because the emergency struck in a "no-fly zone" -- near high-rise buildings, for instance.
When a drone could be sent, the study found, it beat the ambulance 64% of the time, typically by 2 minutes.
The findings were published last week in the European Heart Journal and presented virtually at the European Society of Cardiology's annual meeting.
In a news release from the meeting, Schierbeck acknowledged that weather and other logistics limited the drones' use.
But, she said, "by 2022 we should have drones capable of flying in darkness and in moderate rain. Longer battery life could increase the flight range and the number of inhabitants covered by one drone."
An editorial published with the study points out another issue: None of the AEDs delivered by the drones were actually used by bystanders.
"We also need to work on educating bystanders regarding AED use," wrote Dr. Nicole Karam and colleagues at the University of Paris, in France.
Silva agreed that the study leaves open the crucial issue of what happens after the AED arrives. The "chain of survival," she said, has to include laypeople ready and willing to use the device.
"Drones can deliver an AED, which is all well and good," Silva said. "But we need to know how it impacts patient care."
According to Karam's team, one possible solution is to have emergency dispatchers stay on the phone with bystanders as the AED arrives. Another, they say, is to take advantage of existing smartphone apps that alert people who are trained in CPR of a nearby cardiac arrest. Those alerts could also tell users that an AED is being delivered to the scene.
For now, Silva said people can learn more about responding to cardiac arrest through the American Heart Association's website and others like it, or through classes -- that are often free -- at a local hospital.